Stewart, Sir John (c.1758–1825), 1st baronet, attorney general for Ireland, was born in Co. Tyrone, eldest son among three sons and three daughters of the Rev. Hugh Stewart, rector of Termon, Co. Tyrone, and Sarah Stewart (née Hamilton). Educated by the Rev. R. Norris at Drogheda, he entered TCD (1 November 1774), where he was a scholar (1777), graduating BA (1779) and MA (1806). Deciding on a legal career, he entered Lincoln's Inn in 1779 and was called to the Irish bar in 1781. He had only modest success as a barrister and entered parliament as MP for Augher, Co. Tyrone (1794–7). Named a KC in 1795, in the 1797 general election he was returned for five constituencies — Askeaton, Augher, Bangor, Portarlington, and Strabane — but took his seat for Bangor, Co. Down. Benefiting from the patronage of Lord Abercorn (qv) and the support of the earl of Clare (qv), he was appointed a counsel to the commissioners of revenue in 1797, and became a bencher of the King's Inns a year later. As a reward for his support of government he was made solicitor general in July 1798. He helped draft the articles for the act of union, and gave it vocal support in parliament. After the passing of the measure he was named attorney general in December 1800, serving until May 1803. Disappointed at not being named chief justice of the king's bench, he retired and was created a baronet on 21 June 1803. King George III ascribed his resignation to ill-health and his weaknesses as a law officer.
Concentrating on his career in the united parliament, he sat as MP for Co. Tyrone (1802–6, 1812–25). Facing serious opposition, he did not seek reelection in 1806 but regained the seat in 1812 and held it until his death. Professing to be an independent in the commons, though he owed much to the patronage of Lord Belmore (qv), he opposed catholic relief in 1813 but defended the corn laws two years later. He died 22 June 1825 after being thrown from his carriage.
He married (June 1789) Mary, daughter of Mervyn Archdale (1725–1813) of Castle Archdale, MP for Co. Fermanagh 1761–1800, 1801–2; she died 28 May 1795. They had two sons and one daughter. He was succeeded as 2nd baronet by his eldest son, Hugh Stewart (1792–1854), who served as MP for Co. Tyrone 1830–35.